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The Safety Case and the Risk-Informed
Performance-Based Approach for Management of
US Commercial Low-Level Waste (Paper #190)
Rateb (Boby) Abu-Eid, David Esh,
and Christopher Grossman
Division of Decommissioning, Uranium Recovery, and Waste
Management Programs
Office of Nuclear Material Safety and Safeguards
United States Nuclear Regulatory Commission
IAEA International Conference on Safety of Radioactive Waste Management
November 21-25, 2016 Vienna, Austria
Disclaimer Note
• Certain materials in this presentation involves
ongoing amendments of 10 CFR Part 61 and
implementation final draft technical guidance
document (NUREG-2175).
• We note that the final provisions of 10 CFR Part 61
amendment and the final draft NUREG-2175 are
currently subject to Commission review and
approval.
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Stak
eh
old
er a
nd
Re
gula
tory
Invo
lve
me
nt
Ap
plicatio
n o
f Man
agem
en
t System
C. System Description
D. Safety Assessment
G. Limits, Controls and Conditions
H. Integration of Safety Arguments E. It
era
tio
n a
nd
De
sign
Op
tim
izat
ion
F. M
anage
me
nt o
f Un
certain
ty A. Safety Case Context B. Safety Strategy
IAEA Safety Case Components
(IAEA SSG-23)
US Presidential/Congressional
Commission on Risk Assessment & Risk
Management, 1997
US GAO Risk Management
Framework, 2005
A, B A,B
C, E D, H
D, F,G
C,E
E, F
G, H
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NRC Risk-Informed Performance-Based
Regulations
• The NRC developed a Probabilistic Risk Assessment (PRA) Implementation
Plan (1994). This plan was superseded in 2000 by the Risk-Informed
Regulation Implementation Plan (RIRIP).
• Many of the NRC regulations were based on deterministic and prescriptive
requirements.
• US Low-Level Waste (LLW) regulations under 10 CFR Part 61, developed in
1980’s, were based on risk (dose) to members of the public, risk to
inadvertent intruder, and disposal site performance.
• In April 2007, the NRC replaced the RIRIP with the Risk-Informed,
Performance-Based Plan (RPP). Each of these plans has guided the NRC in
developing risk-informed performance-based regulations and
implementation guides.
• Currently, the NRC is amending its regulations that govern low-level
radioactive waste disposal facilities to require new and revised site-specific
technical analyses (Federal Register /Vol. 80, No. 58 /Thursday, March 26,
2015).
Technical Analysis Techniques and
Deliberation (NUREG-2150)
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Aspects of Safety Case in NUREG-2175
• Strategy for Achieving Safe Disposal of Radioactive Waste;
• Description of the Disposal Site and Facility;
• Description of the Technical Analyses;
• Demonstrating Performance Objectives;
• Strategy for Institutional Control of the Disposal Site;
• Description of Financial Qualifications of the Licensee;
• Description of Other Information; and
• Safety Arguments/Functions.
Revised Part 61 Overview
• Safety case and defense-in-depth protections;
• Site-specific technical analyses (performance assessment,
intruder assessment, site-stability);
• Time of compliance considering waste characteristics;
• Site-specific intruder receptors;
• Waste acceptance criteria may be developed based on the
results of the technical analyses;
• Updated dose methodologies;
• Consideration of uncertainty;
• Model support; and
• Site characteristics consider waste characteristics and are risk-
informed, performance-based.
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Example: Waste Acceptance Criteria
• Allowable Limits
on Radioactivity
• Waste form
Characteristics
and Container
Specifications
• Restrictions and
Prohibitions
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10
CFR
Par
t 6
1 A
ccep
tan
ce
Cri
teri
a
Allowable Radioactivity Limits
Acceptable Waste Form Characteristics and
Container Specifications
Restrictions and Prohibitions
Example: Defense-in-Depth
• The use of multiple, independent, and, where possible,
redundant layers of defense so that no single layer, no
matter how robust, is exclusively relied upon.
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Note: Lifecycle timeframes not to scale
• Identify defense-in-depth protections commensurate with risks.
• Describe capabilities of defense-in-depth protections.
• Provide a technical basis for capabilities of defense-in-depth protections.
Summary/Conclusion Safety Case & 10 CFR Part 61
• Safety Case is an integrated approach to risk assessment and risk management.
• NRC staff explicitly added “the safety case” concept in the ongoing amendment
of 10 CFR Part 61, at the direction of Commission.
• Plain language description the safety arguments and evidence to demonstrate
the overall safety of a land disposal facility were developed.
• It describes all safety relevant aspects of the disposal site, the design of the
facility, and the managerial control measures and regulatory controls to inform
the decision whether to grant a license.
• It includes the same type of information that the original 10 CFR Part 61
required to be submitted as part of a license application (i.e., 10 CFR 61.10 – 10
CFR 61.16).
• The safety case will be updated over time as a new information is gained during
the various phases of the facility’s development, inspection, and operation.
• 10 CFR Part 61 SC is quite consistent with IAEA SSG-23 with more detailed
technical analysis.
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BACK-UP SLIDES
Timeframes
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Waste specific
Who will perform these Technical Analyses? Commercial LLRW Sites in U.S.
US Ecology,
Hanford, WA
EnergySolutions,
Clive, Utah
Energy Solutions,
Barnwell SC
Waste Control
Specialists,
Andrews, TX
Facility Waste Compact
Restrictions
Richland, WA A, B, C 11 Western states
in 2 LLW
Compacts only
Clive, UT A only None, all US
generators OK
(Compacts must
approve)
Barnwell, SC
A, B, C SC, NJ, CT only
(Atlantic
Compact)
Andrews Cty,
Texas
A, B, C Texas and VT
(Texas Compact),
Others with
Compact
approval
Richland, Washington
Operating facility
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Normal Activities
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Dwelling Construction
Agriculture
Drilling for Water
Site-specific Scenarios -
Guidance
• Constrain exposure pathways for normal or
reasonably foreseeable activities based on:
– Physical information
• Waste characteristics and disposal practices
• Disposal site characteristics
– Cultural information (e.g. land use)
• Provide comparison of results from site-specific
scenarios to generic scenarios.
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Site Stability - Guidance
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Waste Acceptance Requirements
• Licensees must review
their waste acceptance
program at least annually
• Ensures that the program
continues to be adequate
and is being implemented
in a way that continues to
protect public health and
safety
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NUREG-2175
• NUREG-2175 (Guidance for Conducting Technical Analyses for 10 CFR Part 61) provides:
─ Flowcharts, NRC staff recommendations, and examples for how licensees can develop high-quality technical analyses
─ Guidelines for what licensees or applicants should include and what regulators should review for each type of analysis
─ Suggested references, screening tools, and case studies
• DRAFT final version made publically available in ADAMS and on the public website
http://www.nrc.gov/about-nrc/regulatory/rulemaking/potential-rulemaking/uw-streams.html
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